<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
</head>
<body>
    <script>
        const vm = {
        _data: {
          name: "laowang",
          age: 18,
          count: 0,
        },
      };
      for (let key of Object.keys(vm._data)){
        Object.defineProperties(vm,key,{
            get: function proxyGetter() {
            return vm._data[key];
          },
          set: function proxySetter(newVal) {
            vm._data[key] = newVal;
          },
        })
      }
    </script>
</body>
</html>